Mechanical stoker.



PATENTED MAY 8, 1906.

W. SEATON, JR. MECHANICAL STOKBR.

APPLICATION FILED APR.14, 1903.

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W. SEATON, JR. MECHANICAL STOKER.

APPLIGATON FILED APR. 14, 1903.

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W. SEATON, JR. MECHANICAL STKER.

APPLICATION FILED APR.14,1903.

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'UNITED STATES PATENT Ncaries'.

MECHANICAL sioxER.

Specification of `Letters Patent..

Batentea May 8, 1906.

Application filed April 14, 1903. Serial No. 152.575.

To @ZZ whom it may concern:

Beit known that I, WILLIAM SEATON, J r., a citizen of the United States, and a resident of New York city, in the county of Richmond and State of New York, have made certain new and useful Improvements in Mechanical Stokers, of which the following isa specification.

Stokers with which I am acquainted are defective either mechanically or thermallythat is, many of them are of defective mechanical design-having many parts subject to the action of the fire and, though reasonably efficient in producing combustion, get out of order and take an excessive power to operate. Those thermally defective obstruct the fire-pit, so that the draft is interfered with and its distribution aected to such an extent as to impair the efficiency of the furnace. A typical one of these stokers is ari ordinary chain grate running over sprocket-s; but this, as is manifest, has a great number of joints which soon corrode and increase the friction of the apparatus. Other serious defects are its obstruction of the access of air to the under side of the fire (since it is manifest that the same part of the grate is in contact with the same part of the re throughout its traverse of the combustion-chamber) and lack of means of agitation of the fire at the'proper times.

The chain grate is merely an example of old constructions upon which I aim to substantially improve by the devices and method of operation which I herein disclose. Other stokers have somewhat similar defects or disadvantages. For these devices I substitute sets of grate-bars which are advanced together and retracted in alternation, one of the sets being retracted while another is stationary. To avoid breaking up the fire to too great extent, thus impairing its eliiciency,`

the bars 'which are being retracted are dropped away from the fire during the motion of retraction. When` they are brought back to their original longitudinal position, they are raised and .again come in contact with the bed of coke or coal, and after both sets advance again longitudinally in the same plane the other set of bars is lowered, lso that the fire now rests on the ones first retracted. This o eration is repeated by the sets of bars in a ternation, the result being the gradual advance of the entire bed of the fire from theY front to the back of the furnace. It is found in practice that the coke or coal soon after it enters the furnace packs or cakes, so that every alternate bar of vthe grate may be lowered as much as is necessary to clear and avoid disruption of the' fire-bed during re4 traction. The caking action referred to makes the coal substantially arch over the openings caused by the withdrawal ofone set of bars, so'that these bars may be retracted without retrogression of the coal. If it should happen with such material as finely-divided anthracite coal that some few particles adhered to the grate-bars with more friction than to the coal-bed above, devices are provided which will interrupt their retrogres-A sion durin the lperiod of retraction.

An inci enta advantage, and one of importance in the practice of the invention, is that the grate-bars may, if desired, be larger and more substantial than those hitherto in use, and since the coal in its active state of combustion does not remain in constant contact with them the bars will not burn out so soon. I believe it to be new with me to provide any mechanism which will alternately expose by sections the entire under surface of the fire to the action of the draft and will also advance the fire properl through the furnace without manual inter erence.

An important and valuable feature ofthe invention is in the carrying forward of the bed of the re substantially without friction over the grate as distinct from pullin pushing, orrocking the coal along. The a ternation of position of the fre supporting parts b which the points of sup ort are shifted and those arts which have eentheretofore exclude from the draft are exposed to it enables me to obtain greatly-improved c ombustion andto avoid the tendency of clinker to set upon the bars. This arran ement also has the advantage of permitting t e portion of the rate in contact with the fire-bed 'to be perio ically subjected to the action of the draft, so that it is cooled below the excessive temperature to which it is often subjected and its life is greatly rolonged.

As coal progresses through) a furnace a progressively-increasing amount of a ltation be, comes necessary 1n order to et e clent combustion.'

This is provided y my improved device. It will be observed that when the coal first enters the furnace it is carried along ICO substantially without agitation and cokes in the heat of the furnace, the gases being carried by the draft toward the stack and consumed. As the bed of partially-coked coal passes on'it ignites and generates intense heat. As the ash accumulates the fire becomes more friable, and as the grate-bars de- .scend the fire now begins to follow them, While at the back of the furnace, beginning at about the line of support for the grate-bars, instead of the latter falling away from the fire they are slightly thrust up into it, so that the i" *ashes are completely disintegrated by the retraction of the bars and sift through into th ash- Y 1t Tiie4 accompanying Ydrawings show 'my in- 'V vention.

In the drawings, Figure 1 is a side elevaf y ftion, artly in section, on line 1 1 of Fig. 2,

the slides M (hereinafter referred'to) not be-` ing shown. Fig. 2 is a plan with certain parts omitted and with the sustaining-frame v of the machine shown partly in section. Fig.

3 'is an end elevation with one set of gratebars and their supporting projections omitted.

Figs. 4 and 4a are perspective detailsA` of part y tail of t of the o erating mechanism. Fig. 5 is a deiie cylinder-support. Fig. 6 is a diagram illustrating the motion ofY selected points upon the front parts of the grate-bars.

Fig. 7 is a perspective detail of the ash-con v veyingdevice.

Referrinjgnow to Figs. 1, 2, and 3, A A are I`bars rming the frame of the machine. These support the entire structure.

view, Fig. 5. The other is indicated partly in section at R3' in Fig. 1,. B B2 are the supporting devices for the interleaved sets of grate-bars,(markedCC2,res ectively.) rlhe supporting-bars B B are t e inner two and movein unison.- B2 B2 are the outer bars and ,alsovmove in unison. Each of them carries on suitable lugs D cross-bars d, having projections d2, upon which rest the grate-bars.

v(See Fig. 3.) The-grate-bars I prefer not -to make of uniform size throu nout their entire length, 'and inasmuch as t e central porf tion of them usually burns out while the ends are still useful I divide them into longitudinal sections, as indicated by the joints c c.

-' (Seen best in Fig. l.) By examining Fig. 2 it will be seen that the portions of the grate-- bars nearest to the ma azine are wider than those in the center an Thus asl the coal enters the. furnace it is suplported on a comparatively solid surface hav- 6o ing only narrow air-spaces between the bars, but 1s subJected to the heat of the fire and its gases are evolved and burn inthe furnace, While the coal itself partially cokes. As it further proceeds into the furnace it arrives at Theyvare connected front and back by cross-bars, one of which forms the support for the operating mechanism and is shown in the detalled back of the furnace.'

the part of the grate where the bars are nari.

rower and there is more space between them, so that a conslderable lncrease of oxygen 1s furnished, generating an intense heat.

. Latches N are provided, which substantially fillthe openings made by the dropping of the bars, as hereinafter described. These exclude any undue amount of. air, and should the coal follow the bars and be carried back.

by them to too reat an extent as they drop vthese latches preventits being withdrawn from the fire and dropped into the pit.

As will be seen from Figs. 1 and-3,ithe .i

frame of the machine is carried upon wheels A2, which run upon tracks O O, so that itmay be withdrawn as a unit from the furnace for repairs. The supporting-bars B B2 are carried at their rear ends upon differential rollerl bearings, one of which is shown at A3 in'Fig. 1. As the supporting-bars B B2 are heavy, I counterbalance so much of their weight as is,

1 and 3,) which are provided with turnbuci kles b2. Enough of their Weight must beleft unbalancedto cause them to move by gravity with certainty.

` 190 The operating mechanism will be best lun-` derstood from Fig. 4 in con'lunction with' f Figs. 2 and 3. In Fig. 4, G is a casting form. .t ing a cross-head attached to the piston-rod-l 1.-'

of the piston F, (see Fig. 1,) reciprocatingin .'95-y the cylinder E.' Any suitable power maybe 'l used to operate the mechanism; I prefer i hydraulic pressure, because this can usually y' be provided without undue expense and. bei 1,09 y

cause the action of electric rotary mechanisms must be geared down to an'objectionable extent to make them operate slowly, v. enough; but the latter may be employed, if-

desired. Att-achedv to the cross-head G are i two inclines G G2, provided with lips g. They ends of the supporting-bars B B2 are similarly inclined and are provided with lugs b3' I b4 on the bar B and b5 b2 on the bar "132." f

These lilgs coperate with guides A4 A5, secured to fixed portions of the mechanism. The guide A4 cooperates with the lugs b on the bar B2, as shown in Figs. 1, 2, 3, and 4,

while the lug Vb3 cooperates with one vof the guides A5, as seen in Figs. 1, 2, and 3. The i lugs b4 b5 overlap and cooperate with one anvd presently more fully explained.

Fig. 5 shows the supporting device for the I' f cylinder and 'cross-head and the attachedk parts of the latter. The reference-letters.,re-v

fer to parts already described, and a detailed v desirable bysprings b b2, (seen best in Figs.

I r5` other, as best seen in Figs. 2 and 3 and as l their entire length in the rear, since they are supported upon the roller A3, and therefore do not rise and fall at that point, their motion being there substantially entirely longitu'dinal, while beyond that point the vertical movements are reversed in direction, the ends of the bars instead lof being dropped away from the fire being (as already pointed out in my statement of invention) thrust up into it.

In Fig. 7, P illustrates a part of the mechanism of the ash-conveyer. (See also Fig. 1.) This acts `to bring-the ashes forward to the front of the pit.- P- is the shank. P2 is the lower part or bar, which is hinged to the upper one and carries the shovel P3. A lug p on the bar P2, engaging with the back of shank P', permits the shovel to drag over the ashes as the mechanism passes toward the back of the furnace, but causes `it to bring the ashes along as it is retracted. It is manifest that the direction of the movement of the ash is according to the convenience of the engineer. In the drawings I have shown ash-pits both in front and rear; but ordinarily only one would be used. When using a pit in the rear, a screen L is attached to the framework of the machine, so that the draft would not be unduly affected by openin the ash-pit door. These details, however, orm no part of my invention and are left to the discretion of the manufacturer.

The operation of the device as thus described is as follows: As seen in Fig. 1, the piston F has just completed its stroke, the parts being ln the position shown in Fig. 4. As it starts away from the furnace the crosshead G carries with 'it inclines G G2 over the slides M M and the lips g g engage with the hooked ends of the bars B retracting them, the lugs b4 passin under the lugs b5 on the bars B2 B2 and the ugs b5 passing under the fixed uides A5. The inclines move away from th'e ars B2 B2, leavin them supported by the lugs b u on the gui es A4 A4. When the piston reac es the end of its stroke, the ends of the bars B B will be in advance of B2 B2, or to the left of them` in Fig. 2. The piston now moves toward the furnace, carrying with it the cross-head Gand-inclines G G2; The first effect of this motion is to raise the ends of the bars B B until they are in the same plane as the bars B2, bringin all the grate-bars into the same horizontal p ane, or substantially so, and engaging the rear faces of the lugs b4 on the bars B with the front faces of the lugs b5 on the bars B2. All

the bars are then carried along for half the stroke of the piston. The bars B B then engage by the lugs b5 b2 with the uper surface of the uides A5 A5, the lugs b 4 being in front o and enga in with the lugs b5 b5 on the bars B2 B2, and a fittle later the lugs b5 on the bars B2 B2 reach the ends of the guides A4 A4, and these bars are then depressed, as the others take their places upon the guides A5 A5. The piston is again at the right-hand end of its stroke, as seen in Fig. ll, but now the bars B2 B2 are depressed and B B are elevated, as shown in Fig. 4a. The piston F now'starts again toward the left, or away from the furnace, carrying with it the inclines G G2, the lips g upon which engage with the hook ends of the bars B2 B2. The lugs b3 b2 u on the bars B B rest in their turn upon t e guides A5 A5. (See Figs. 2 and 3.) These bars are therefore stationary during the further outward movement of the crosshead and the inclines G G2. When the piston reaches the end of its stroke on the left, or away from lthe furnace, the lugs b5 b6 on the bars B2 B2 are just in advance of the front faces of the guides A4 A4- and the lugs b5 b5 are in advance'of and below the lugs b4 b4 upon the bars B B. rI he piston now starts toward the right, or toward the furnace, and the first effect of this motion is to elevate the ends of the bars B2 B2, so that the bottom of the lug bcoincides in plane with the top of guide A4, and the rear face, or that on the right of the lug b5, is in advance of the front face, or that on the left of the lug b4 on the bar B. Inasmuch as the faces of the inclines are not subjected to the heat of the re, they may be freely lubricated with any good cylinder-grease, and the friction from the weight of the coal at the back of the furnace suffices to prevent premature longitudinal movement. The piston continuing this course. The lips at the top of the incline now engage with the ends of the bars B2 B2. They in turn (by the lugs, as already pointed out) enga e with the bars B B, and thus all of the re-supports are forced toward the back of the furnace until the piston again arrives at the right end of the cylinder, as seen in Fig. 1. In the meantime the bars B B have passed so far forward that the lugs b5 b3 have dropped off the guides A5 A5, the lugs b b5 have taken their places u on the guides A4 A4, as shown in Fig. 4, an the cycle of operation is complete.

The action of the ash-conveyer, it is believed, is evident without detailed explanation.

I believe it to be new with me to combine reciprocating motion in a grate with an ashconveying arrangement operated by the same motion to carry the ashes forward or back, as may be desired.

Changes may be made in the arrangements indicated without departing from my invention. The precise figure described by the grate-bars is unimportant. I believe the one which I have indicated to be substantially the only one which should be used'in practice, because the mechanism to obtain other motions must necessarily be more IOO IIO

complex; but Ido not mean to confine myself 1n that respect.

I have designated the particular outline described by a selected point on the fire-surface of the grate-bars as four-motion feed in analogyto the feeding device in a sewing- .machine, which is well known by that name.

It is only essential that this motion should be represented by a substantially straight-sided closed figure a straight side of which is coincident in plane with the fire-bed. In using the termlfourmotion feed I use it in an indicative sense, not meaning to exclude feeding motions, the outline of which is represented by other figures having different numbers of sides, provided that the straight side which the point describes is in contact with the fire, although I prefer the four-sided figure for the reasons just pointed out..

My invention does not llmit me to the precise forms of the devices indicated in the drawings. The particular feature, which consists of the four-motion feed of the alter-l nating sets of bars, ma 7be applied to many forms of existing sto ers with only such changes as are obvious to those skilled in the a'rt. Chains vor bars divided into any desired number of sets-steam, electric, or other power-may be used, and other changes may be made and still embody the invention.

- None of these formal changes has been illustrated, since their embodiment is within the skill of a'ny constructing engineer. For eX- ample, no valves for the control of the power driving the cylinder are illustrated or described. Any desirable connection of this character may be made by the engineer, and as they would necessarily vary with the class of power employed I have preferred not to illustrate them.

Having thus described my invention, what I claim, and desire to protect by Letters Patent of the United States, is-

1. In a mechanical stoker, the combination of a plurality of interleaved sets of grate-bars, with means for imparting' a feeding motion simultaneously to the Isets and for lowering andv retracting the different sets separately.

2. In a mechanical stoker, the combination of a plurality of interleaved sets of movable grate-bars with means for imparting to the sets, simultaneously, a series of distinct motions to feed the fuel, and for lowering and retracting the different sets separately.

3. In a mechanical stoker, the combination of a pluralityof interleaved sets of ygrate-bars with means for imparting a feeding motion in a common plane, simultaneously to the sets, and for lowering and retracting the different sets separately and in alternation.

4. In a mechanical'stoker, the combination of interleaved sets of fire supports, with means for imparting to them a motion the outline of which is a substantially straightl sided closed igure,'a straight side of which is coincident inplane with the bottom of the fire; the sets of fire-supports being moved forward simultaneously when thus coincident, and being lowered and retracted in alternation.

5. In a mechanical stoker, the combination of interleaved sets of re-supporting devices with means for imparting thereto `in alternation a fourmotion feed, the upper movement of one being partly coincident in plane with the upper movement 'of the other 5 the motions of the sets bein simultaneous upon their upper lines o movement and successive in the other parts of their motion.

6. In a mechanical stoker, thecombination for imparting to them a motion, the outline of which is substantiallyv a straight-sided closed ligure, the motions of the fire-supthe sets being stationary while the other is retracted; whereby, during the longitudinal movementv of the sets, 'they simultaneously advance the fire, and while any set is lowered and retracted, the fire is maintained stationif. In a mechanical stoker, the combination means for imparting to the sets inalternation a four-motion" feed; the motions of the sets of' bars overlapping, in` the upper parts of the movement being simultaneous the bottom ofthe re,'and one set of bars being lowered and retracted while the other is maintained stationary.

8. In a mechanical stoker, the'combination with interleaved sets of grate-bars, of means for moving the sets `in alternation in such manner that similar points on the re-supporting surface of the bars in different sets Zoids, the upper sides of whic coincide-1n plane with the bottom of the fire; all of the sets moving forward to ether, and some remaining stationary whi e others are lowered and retracted.

of a number of interleaved sets of grate-bars, means for causing all of the sets to move forplane, means for lowering one set out of contact with the fuel and retracting it while maintaining the remainder of the bars stationary in the normal plane, means for restoring the retracted bars to the normal plane and causing all of the bars to move forward therein, and means for repeating with another set of bars the movements of the first set.

10. The combination, in a mechanical stoker, of interleaved sets of grate-bars With ports overlapping longitudinally and one of ward longitudinally in a common normal of interleaved sets of fire-supports with means with two sets of interleaved grate-bars, of,

and substantially coincident in plane with substantially describe overlapping trape- 9. In a mechanical stoker, the combination means for advancing them all in a common plane' When in contact With `the lire, and means for keeping some of them stationary, and lowering and retracting others While out of contact With the ire.

l1. The combination, with .a mechanicl ally-operated grate, having a reciprocating movement, of a reciprocating ash-conveyer consisting of a serles of Jolnted shovels at- 

